Gasket cut-through prevention closure and container

ABSTRACT

A tamper-proof closure cap of the type having a shell formed with a top panel portion and a depending skirt portion with an annular gasket having appreciable thickness disposed in the outer margin of the top panel. In a preferred embodiment the skirt portion for a substantial part of its height has an outwardly tapered or flared frusto-conical section with a predetermined angle for matching engagement on the correspondingly tapered or flared frusto-conical side finish of the neck of a container so as to positively limit the downward seating movement of the cap on the container neck. Alternately, the skirt may have a curl, bead or seam formed on its bottom edge which engages continuous or interrupted shoulder means on the neck for positively limiting the downward seating of the cap on the container neck. The container for use with the closure cap also has an annular top rim finish for sealing engagement into the gasket. On application the closure cap is pressed over the container neck until seated and retained in place by means of headspace vacuum until removal. It can be readily removed by rupturing a pre-formed vent in the top panel portion such as by lifting on a ring pull tab.

United States Patent Westfall et al. 451 A 29, 1972 1 GASKET CUT-THROUGH Primary Examiner-George E. Lowrance PREVENTION CLOSURE AND Attorney-(heist, Lockwood, Greenawalt & Dewey CONTAINER [72] Inventors: James E. Westfall; Donald H. [57] ABSTRACT Zipper, both of W t S i I1} A tamper-proof closure cap of the type having a shell A C ml C C I formed wlth a top panel portion and a dependmg sk1rt Sslgnee' on men an ompany portion with an annular gasket havmg appreciable New York thickness disposed in the outer margin of the top [22] Fil d; J l 15, 1970 panel. ln a preferred embodiment the skirt portion for a substantial part of its height has an outwardly [21] Appl' N05 54,900 tapered or flared frusto-conical section with a predetermined angle for matching engagement on the 52 U.S. Cl. ..220/42 A, 215/40, 220/44 R, cofrespondingly tawed or flared frusw-cvnical Side 220/46 R fimsh of the neck of a container so as to positively 51 1m. (:1 ..B65d 51/16, 1305a 41/12 limit the downward Seating movement of the Cap [58] Field of Search A 42 C 44 R 46 R; the container neck. Alternately, the skirt may have a 215/40 curl, bead or seam formed on its bottom edge which engages continuous or interrupted shoulder means on [56] References Cited the neck for positively limiting the downward seating of the cap on the container neck. The container for UNITED STATES PATENTS use with the closure cap also has an annular top rim finish for sealing engagement into the gasket. On apggfif i plication the closure cap is pressed over the container 3243075 3/1966 Reinke A neck until seated and retained 1n place by means of 3283946 11/1966 Stec headspace vacuum unt1l removal. It can readily 23 2 11/1970 Wes "2 R X removed by rupturmg a preformed vent 1n the top 2:273:247 2/1942 Barnby ..220/42 A panel porno Such as by lftmg a pun 5 Claims, 4 Drawing Figures PAIENTEDmszs I972 INVENTORS JAMES E. WESTFALL I 0 ALB H. P R

BY TT YS GASKET CUT-THROUGH PREVENTION CLOSURE AND CONTAINER This invention relates to innovations and improvements in closure caps which are not subject to gasket cut-through and are tamper-proof, vacuum-retained, non-resealable, and have low oxygen permeability.

More specifically, the invention relates to closure caps of the class described wherein in one embodiment the depending skirt portions have sections thereof formed with a downward and outward predetermined taper for matching a mating correspondingly tapered surface on the neck of a container thereby limiting rather precisely the extent to which a cap can be pressed down on any container. The closure caps and the matching sealing surfaces of the containers will be so inter-proportioned that a predetermined clearance space for accommodating compressed gasket material will be provided between the top rim sealing surface on the container neck and the opposing marginal portion of the closure cap shell. The clearance space positively prevents gasket cut-through this being a very definite hazard with top seal press-on caps when subjected to the high temperatures required in aseptic processing.

As a practical alternative to the matching tapers positive predetermined clearance space can also be obtained by having the bottom edge of the cap skirt or flange engage a shoulder or abutments formed on the container neck.

A further feature of the invention is the provision of closure caps of the class described which cannot be readily removed without destroyu'ng the vacuum that holds them in place and wherein the top panel portions are provided with rupturable vents with suitable lifting means whereby the closure caps can be readily removed by authorized persons simply by rupturing the vent, thereby breaking the vacuum that retains the cap in place, then lifting the cap from the container neck. The rupturable vents may be formed in such a way that any resulting sharp edges formed when the vent is ruptured are directed toward the cap exterior so that if a person such as a child should lick the interior of the cap his tongue will not be cut by the sharp edges in the vent area.

Press-on, vacuum retained, closure caps are well known in the art. Caps of this type are relatively inexpensive and are valued by food packagers because of their ease of application at high speeds. They are firmly retained in place by reason of vacuum created in the head space on condensation of an atmosphere of steam which occupies the head space when the caps are initially applied and sealed. Machines for applying such press-on closure caps at high speeds have been commercially available in the country from several sources for a number of years.

The object of the present invention, generally stated, is the provision of closure caps of the class described which are not subject to cut-through and are tamperproof, vacuum retained, non-resealable, exhibit low oxygen permeability, and are readily removed by rupturing a pre-formed vent without leaving sharp edges exposed on the interior of the closure cap.

A more specific object is the provision of a closure cap of the foregoing type with a section of the skirt or flange of the cap shell having a predetermined angle of outward taper for matching seating engagement against a correspondingly tapered section of the exterior finish of a container neck thereby positively limiting the downward seating movement of the closure cap on the container neck so as to leave a predetermined space for gasket material to be compressed between the top panel portion of the closure cap shell and the top seal finish of the container rim. Alternatively, limited downward seating movement may be obtained by having the bottom edge of the cap skirt or flange engage a shoulder or abutments on the container neck.

'A further object of the invention is the provision of closure caps of the class described wherein the cap shells are formed of aluminum which lends itself to the taper-to-taper matching engagement and to the formation of a rupturable vent in the top panel portion of each cap.

Certain other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.

For a more complete understanding of the nature and scope of the invention reference may now be had to the following detailed description thereof taken in connection with the accompanying drawings, wherein:

FIG. 1 is a top plan view of a closure cap forming one embodiment of the present invention;

FIG. 2 is a fragmentary sectional view on an enlarged scale taken on line 2-2 of FIG. 1 showing the details of the manner in which the closure cap seats and seals onto the top rim and neck of a container;

FIG. 3 is a fragmentary sectional view taken on line 3-3 of FIG. 1, showing the vent in the top panel portion ruptured as a result of lifting the pull ring tab; and,

FIG. 4 is a fragmentary sectional view corresponding to the left-hand portion of FIG. 3 and showing an alternate form of the invention in which a bead formed on the bottom of the cap skirt or flange engages a shoulder on a container neck to limit downward movement of the cap so as to thereby prevent gasket cutthrough.

Referring to FIGS. 1-3, a closure cap is indicated generally at 5 comprising a shell which has a flat top panel portion 6 with a raised annular channel 7 at the margin and a depending skirt or flange 8 at the periphery. The cap shell may be stamped or otherwise formed from aluminum sheet tin plate, or other suitable material, in a manner well known in the art. The shell may be suitably enameled or lacquered on the interior and exterior with protective and decorative enamels or coatings which are also well known in the closure cap art.

The annular channel portion 7 at the margin of the cap top panel serves as a retainer for a flowed in gasket 10 which may be formed of plastisol and deposited into the cap and fluxed in place therein in known manner e.g. as disclosed in Zipper US. Pat. No. 2,841,304. Normally, the gasket 10 will have a vertical height or thickness approximately equal to the depth of the channel 7 which also corresponds generally to the vertical dimension or height of the circumferential shoulder 11 which forms the inner wall of the channel 7.

In FIGS. 2 and 3 the cap 5 is shown in pressed-on, vacuum-retained, sealing engagement on the neck finish 12 of a container indicated generally at 13. While the container 13 is shown as being formed of metal, it will be understood that it could be formed of glass or plastic. The neck 12 of the container 13 is formed with an inwardly rolled head 14 the top surface of which provides an annular top seal finish which is adapted to press into or indent the annular gasket in sealing engagement as shown.

The flange or skirt 8 on the closure cap 5 terminates at the bottom in a flattened seam or bead and upwardly thereof the skirt or flange 8 has a tapered or outwardly flared frusto-conical waist section 16 which engages and seats on a correspondingly outwardly flared or tapered frusto-conical section 17 of the container neck 12. It will be noted that the balance of the skirt 8 has a different conformation than the section 16. The waist section 16 and the band section 17 are accurately formed to have the same angle of taper with the inner diameter of section 16 and the outer diameter of section 17 being equal. By reason of the interengagement of the tapered sections 16 and 17, the downward movement of the closure cap 5 onto the container neck 12 is limited so that the rim on the bead 14 on the container neck 12 cannot approach the horizontal portion of the channel 7 any closer than is shown in FIGS. 2 and 3. This prevents direct contact between the rim or bean l4 and the channel 7 which would result in cutthrough of the gasket 10. Cut-through is most likely to occur in closure caps of the type shown when they are subjected to the high temperatures such as are encountered in aseptic processing of various food products. Plastisol and other gaskets become much less resistant to cut-through at such elevated temperatures. it will be understood that if cut-through occurs then the sealing ability of a closure cap is substantially impaired and may result in a leaker.

The closure cap 5 is shown provided in its upper panel 6 with a rupturable vent which may take the form of an integral rivet 20 formed in known manner. Such rivets are employed for example in the ends of cans of beer and carbonated beverages. This rivet-like portion 20 is secured in known manner to the tab portion 21 of a lift ring 22. The closure caps 5 are manufactured with the ring 22 and tab 21 lying flatwise on the top surface of the panel 6. The material is weakened around the rivet so that on lifting the ring 22 the rivet portion ruptures and can be lifted away as shown in FIG. 3. When this occurs the top panel portion is provided with a vent opening which is indicated at 23. The raw edge of the opening 23 projects outwardly as indicated at 24. By reason of this feature and the small size of the vent opening 23, a person may safely lick the interior of the cap 5 to remove any contents of the container that may adhere. It will be noted that the edge 24 is shielded by the tab portion 21.

Closure caps S can be readily applied at high speeds to filled containers by commercially available capping machinery. The air or atmosphere in the small head space left in the filled containers is displaced by steam in the capping operation and after the caps 5 are pressed down in place on the container necks so as to form an initial seal in the capping machine the vacuum which develops on condensation of the steam in the head space securely holds the caps in place.

In the cap and container relationship shown in FIGS. 2 and 3 it is very difficult to remove one of the caps 5 as long as it is retained in place by vacuum. Furthermore, if an attempt is made to remove one of the caps 5 by prying or lifting underneath the flattened seam 15 the flange or skirt 8 will be mutilated or sufficiently distorted so as to reveal that tampering has occurred.

However, the cap 5 can be readily removed by simply lifting the ring 22 and rupturing the integral connection of the rivet 20 to the main portion of the top panel 6. The small vent 23 allows the vacuum to be broken and thereupon the cap may be readily lifted off without distortion. A person, such as a customer in a self-service supermarket, can readily tell if someone has tampered with a closure cap 5 and ruptured the vent since the ring 22 will be lifted at least slightly and the cap will be loose on the container.

Referring to FIG. 4 of the drawings an alternate embodiment of the invention is shown wherein the underside of the flattened bead 15' engages and bears on the upper side of a shoulder 19 formed on the neck of the container indicated generally at 13'. In this embodiment there is no interfitting of tapered sections on the skirt 8' of the cap 5 and the neck 12' of the container 13'. Since no space is to between the underside of the seam or bead 15' and the caps supporting shoulder 19 for a person t insert a knife edge, for example, the cap 5' is also tamper-proof but may be readily removed by rupturing the vent opening in the top panel portion as described in connection with cap 5.

Instead of employing an integrally-formed rivet 20 in the top panel the manually rupturable vent menas may take the form of a small opening covered and closed with an adhesively secured tape provided with a lift tab. The tape should have adequate resistance to oxygen and air permeation. Adhesively secured lift tab tapes of this type are currently used commercially for closing pour-out opening in the ends of cans.

What is claimed as new is:

l. A closure cap for hermetically sealing a container having an annular gasket-engaging top seal finish on the container rim and having a side finish on the container neck including a downward, outward tapered frusto-conical finish portion having a predetermined angle of inclination or taper, said closure cap comprising, a shell having a top panel with an annular gasket receiving channel therein at the margin and a depending skirt, and a top seal gasket at least substantially filling said channel for indented sealing engagement with said annular gasket-engaging top seal finish, said skirt having in the mid-portion thereof a downward and outward tapered frusto-conical portion with the same angle of inclination or taper as that of said frusto-conical finish portion on said container neck for matching seating engagement thereon the remainder of said skirt having a different conformation from said frusto-conical portion thereof, said matching seating engagement serving to limit the downward movement of said closure cap shell on said container neck thereby preventing cut-through of said top seal gasket.

2. The closure cap of claim 1 wherein said top panel portion of said closure cap shell has a gasket-receiving channel at its outer margin with said top seal gasket being at least primarily disposed therein.

3. The closure cap of claim 1 wherein said closure cap shell is formed of semi-rigid material whereby said skirt portion is sufficiently deformable to achieve said matching engagement with said container neck when said frusto-conical surface on said cap skirt is slightly out-of-round.

4. The closure cap of claim 3 wherein said closure cap shell is formed of aluminum.

5. The closure cap of claim 1 wherein said top panel portion of said cap shell has a rupturable vent therein and manual lifting means attached to said vent. 

1. A closure cap for hermetically sealing a container having an annular gasket-engaging top seal finish on the container rim and having a side finish on the container neck including a downward, outward tapered frusto-conical finish portion having a predetermined angle of inclination or taper, said closure cap comprising, a shell having a top panel with an annular gasket receiving channel therein at the margin and a depending skirt, and a top seal gasket at least substantially filling said channel for indented sealing engagement with said annular gasket-engaging top seal finish, said skirt having in the mid-portion thereof a downward and outward tapered frusto-conical portion with the same angle of inclination or taper as that of said frusto-conical finish portion on said container neck for matching seating engagement thereon the remainder of said skirt having a different conformation from said frusto-conical portion thereof, said matching seating engagement serving to limit the downward movement of said closure cap shell on said container neck thereby preventing cut-through of said top seal gasket.
 2. The closure cap of claim 1 wherein said top panel portion of said closure cap shell has a gasket-receiving channel at its outer margin with said top seal gasket being at least primarily disposed therein.
 3. The closure cap of claim 1 wherein said closure cap shell is formed of semi-rigid material whereby said skirt portion is sufficiently deformable to achieve said matching engagement with said container neck when said frusto-conical surface on said cap skirt is slightly out-of-round.
 4. The closure cap of claim 3 wherein said closure cap shell is formed of aluminum.
 5. The closure cap of claim 1 wherein said top panel portion of said cap shell has a rupturable vent therein and manual lifting means attached to said vent. 